#loading-message {
  position: absolute;
  width: 100vw;
  top: calc(50vh - 1em);
  text-align: center;
}

#loading-message #loading-spinner {
  display: inline-block;
  animation: loading-spinner 0.7s ease-in alternate infinite;
}

@keyframes loading-spinner {
  0% {
    transform: translate(0, -2em);
  }
  100% {
    transform: translate(0, 0em);
  }
}